Articulated structural parts, for example those for constant velocity joints, are usually produced by drop forge technology, but may also by produced by machining tubes, rods and the like. These articulated structural parts are particularly exposed to stresses on the bearing surfaces, such as between connected outer joint parts and inner joint parts. Cracks often appear during operation of these parts because of the surface stresses, which may expose the articulated structural parts to a correspondingly faster wear.
Articulated structural parts, e.g., constant velocity joints having a joint cage, an outer joint part and an inner joint part, are usually produced from inductively hardenable structural steel having a carbon content in the range of about 0.45% by weight to about 0.55% by weight calculated on the total weight of steel. These types of structural steels, such as standardized carbon structural steel, e.g., CF53, containing about 0.5% by weight of carbon calculated on the total weight of steel, are typically used for the production of articulated structural parts. Accordingly, shaped objects produced for standardized carbon structural steel may be subsequently hardened e.g. by induction hardening, whereby, as a result of the induction hardening, a relatively fine-grained wear-resistant surface is obtained. A disadvantage of this method, however, is the low hardness of the structural parts, and also, in particular, the low resistance to crack propagation.
Accordingly, it would be advantageous to provide an articulated structural part having improved hardness. Moreover, it would be advantageous to provide an articulated structural part having crack propagation resistance.